Efforts in the next year will build on the foundations laid from the work in the past two years. First, the computerized image processing will be extended to three dimensions using the fluorescent Drosophila sperm heads and mitotic chromosomes as examples. These methods will be continued to be applied to the high voltage EM micrographs so as to further interpret, at high resolution, the helical structures present in the interphase nuclei. Second, the 3D arrangement of the polytene chromosomes in intact nuclei in salivary glands will continue to be determined. The computer methods are especially tailored for solving this problem. Also aiding are the nuclear protein monoclonal antibodies made by Dr. George Kuo and (genetic) chromosome aberrations such as inversions. Extension of these methods and approaches to the diploid state will be made in Drosophila early embryos and the spermatocyte lampbrush chromosome systems.